Roux (/ruː/) is a mixture of flour and fat cooked together and used to thicken sauces.[1] Roux is typically made from equal parts of flour and fat by weight.[2] The flour is added to the melted fat or oil on the stove top, blended until smooth, and cooked to the desired level of brownness. A roux can be white, blond (darker) or brown. Butter, bacon drippings or lard are commonly used fats. Roux is used as a thickening agent for gravy, sauces, soups and stews. It provides the base for a dish, and other ingredients are added after the roux is complete.[3]